Growth on under side of eye lid

I noted a bump on my son's eye a few days after Christmas.  When looking directly at him it appears to be a raised bump on the eye lid. However upon touching it I could tell it was something under his eye lid.  Tonight I noticed it again and asked if he could turn his eye lid upward to that could see if it was a growth.  The growth is the same color of the underside of his eye lid. It shaped like a polyp. He does not c/o pain.  He couldn't lift his eyelid again for me so I can't determine the size or get a photo. I will make him an appointment however any ideas of what it might be?